The present invention relates to floor maintenance apparatus and more particularly to rotary floor polishers.
Floor maintenance machines are used for scrubbing, stripping, polishing or buffing a floor surface. Such machines typically have a rotary floor treating element engaging the floor surface and rotated about its vertical axis by an electric motor, a drive transmission between the motor and the brush and an operator's handle. The machine rests on the floor surface and is typically swept through an arc by variations in pressure exerted on the control handle by the operator. In commercial applications, such machines are subjected to heavy use and must be reliable in operation. Reliability may be sacrificed due to competing desirable attributes such as ease of operation, ease of maintenance, ease of storage, low noise levels during operation and ease of and cost of manufacture.
Examples of prior floor maintenance machines may be found in U.S. Pat. No. 1,847,323, entitled FLOOR MACHINE and issued on Mar. 1, 1932 to Yutzler et al, U.S. Pat. No. 2,348,268, entitled FLOOR SCRUBBING MACHINE and issued on May 9, 1944 to Smith, U.S. Pat. No. 2,561,279, entitled FLOOR MAINTENANCE MACHINE and issued on July 17, 1951 to Holt, U.S. Pat. No. 2,817,977, entitled DRIVE UNIT FOR FLOOR TREATING MACHINES and issued on Dec. 31, 1957 to Holt, U.S. Pat. No. 3,074,089, entitled COMPACT MACHINE and issued on Jan. 22, 1963 to Brown, Jr., and U.S. Pat. No. 3,619,848, entitled APPLIANCE FOR CLEANING FLOORS and issued on Dec. 16, 1971 to Salzmann.
Prior art devices such as disclosed in the aforementioned U.S. Pat. No. 2,817,977, have supported the drive motor in co-axial relationship with a gear reduction unit and the circular brush element. The unit of this patent includes a closed chamber within which multiple gear sets transmit rotary motion. A liquid lubricant is employed to increase the life and hence reliability of the floor treating machine and also reduce noise levels associated with operation.
Mounting the drive motor in co-axial alignment with a drive unit and the brush element results in a vertical height of the polisher which may restrict the areas of usage of the device due to interference with structures found in a building. For example, the machine may not fit under tables or shelves.
Previous attempts to reduce the overall vertical height of the floor treating machines have included offsetting the electric motor from the vertical centerline of the rotary brush. An example of such an arrangement may be found in the aforementioned U.S. Pat. No. 1,847,323. A floor polisher is disclosed therein wherein the drive motor is mounted on a base plate in a position offset from the vertical centerline of a circular brush. Rotary motion is transmitted to the brush by a drive arrangement including a pinion gear secured to a vertically oriented motor output shaft and a ring gear carried by a brush carrier. The pinion gear and ring gear are positioned within a housing which defines a sealed lubricant chamber. With such an arrangement, problems may be experienced with providing adequate lubrication for a bearing structure which supports the brush carrier for rotary motion relative to the housing. Other problems which have been experienced with the prior art floor polishers as illustrated in the aforementioned patents are related primarily to difficulties in manufacture, complexity and in performing routine maintenance on the machines.